This invention relates to stationary, industrial, gas turbines, more specifically to an improved combustor liner for stationary, industrial gas turbines to reduce pollutant generation.
Many large producers and industrial users of electric and other forms of power, such as public utility companies and other corporations, in past years, installed large stationary, industrial gas turbines for incremental, peak, and emergency power production. At the time of installation, those industrial gas turbines were capable of operation at acceptable levels of pollutant generation.
For a number of years, the demand for power remained at a constant level, and these gas turbines were operated as intended, typically for one or two hours per day. However, increasingly stringent regulatory controls were imposed on the industrial generation of pollutants such as NO and NO2 (NOX). Nevertheless, operation of the older gas turbines for one or two hours per day was still tolerable because their pollution production was a small fraction of the total pollution produced in all power generating operations. During this period of time, very little new power generation capacity was installed because the demand for power did not increase. However, a significant rise in power demand has been experienced recently, and the supply from available steady generation machinery has been exceeded. Operation of the older gas turbines for longer periods of time is desired to supplement the existing steady power generation capacity. However, operation of the older gas turbines for longer periods at their formerly acceptable levels of pollutant generation is not now acceptable for both for regulatory reasons and negative environmental impact.
Replacement of these older gas turbine installations with new installations designed specifically for operation with lower pollutant production is unattractive because of the high initial cost of the newer machines. While the pollutant production of the older gas turbines may be reduced by installing and using water and/or steam injection, this involves additional investment, higher operating cost, added complexity, and greater maintenance. Other design modifications proposed to achieve lower pollutant generation are even more costly and unattractive. What is needed is an inexpensive modification for these existing industrial gas turbines which will reduce their pollutant production without increasing operating cost.
This invention satisfies the above needs. The invention provides a novel liner for stationary, industrial gas turbine combustors. An existing liner may be readily reworked to include the novel features. The novel liner comprises an upstream end, a wall extending downstream from the upstream end, a fuel injection location within the liner at the upstream end of the liner, and combustion air openings in the liner wall sized to admit from about 10% to about 25% of the total mass airflow entering the liner. The combustion air openings preferably are located not more than about 0.5 equivalent diameters downstream of the fuel injection location. The combustion air openings may include swirler openings located to admit airflow around the fuel injection location, and penetration air openings located from about 0.4 to about 0.5 equivalent diameters downstream of the fuel injection location. The liner further comprises suppression air openings in the liner wall from about 0.3 to about 0.5 equivalent diameters downstream of combustion air openings located furthest downstream, which usually are the penetration air openings. The suppression air openings are sized to admit from about 0.8 to about 4 times the mass airflow entering the liner through all of the combustion air openings. The liner further comprises wall air openings distributed in the liner wall for cooling the wall and sized to admit from about 10% to about 40% of the total mass airflow entering the liner.
A preferred embodiment of the novel liner further comprises profile air openings in the liner wall located downstream of the suppression air openings and sized to admit from about 10% to about 20% of the total mass airflow entering the liner. Preferably the profile air openings are from about 0.9 to about 1.5 equivalent diameters downstream of the suppression air openings.